Experimental Research on Indicator Diagrams of a Water Lubricated Screw Air Compressor

In recent years, water-lubricated screw compressors have attracted more and more attention, because this type of compressors can produce the high quality air completely free of oil and there is no contamination. However, poor sealing and lubricating properties of water might result in different operating characteristics compared with those of oil-injected compressors. A good understanding of the operating mechanisms is essential in any attempt to increase the performance of the compressor, which can be achieved by means of the indicator diagram. In this paper, a prototype of the water-lubricated screw air compressor was developed and a test rig was established. A series of pressure transducers were arranged in consecutive positions of the casing to measure the pressure distribution inside working chamber of the compressor. In addition, volumetric efficiency, adiabatic efficiency and mechanical efficiency of the compressor under different operating conditions were calculated based on measured volumeric flow-rate and power consumption. As a result, the influence mechanisms of rotating speed, discharge pressure and water injection flow-rate on the compressor performance and working process were analyzed based on indicator diagrams

Experimental investigation on an ORC twin-screw expander with an emphasis on its suction process

Organic Rankine Cycle (ORC) is an effective and promising technology to recover low-grade waste heat and output electricity. As a key component in an ORC system, the expander’s performance significantly affects the whole system’s efficiency. Twin-screw expander is widely employed for its compact structure, reliability, two-phase tolerance and high efficiency. To investigate the characteristics of twin-screw expander, a test bench was set up in a laboratory taking 120 waste steam as heat source. R245fa was selected as the working fluid. Pressure sensors with high sensitivity and accuracy were installed at appropriate locations in the expander casing to monitor the p-V indicator diagrams. The expander’s p-V indicator diagrams and operating parameters were recorded under different operating conditions. The effects of rotational speed and suction pressure on the expander’s suction pressure drop, volumetric efficiency and indicated adiabatic efficiency were studied. Results show that rotational speed and suction pressure affect the suction pressure drop altogether, which has a significant effect on the density and mass flow rate of the sucked gas. The expander volumetric efficiency is above 85% and the indicated adiabatic efficiency can also reach 82%

Study on the characteristics of a novel wrap-around cooled diaphragm compressor for hydrogen refueling station

This study introduces a novel wrap-around cooled diaphragm compressor, designed for employment in hydrogen refilling station. The performance of this innovative compressor is evaluated using a specially developed experimental platform. The analysis focused on the impact of pressure ratio and suction gas temperature on the compressor's performance, and the cooling effect is assessed under varying temperatures of the cooling medium. The findings indicate that both the isentropic and volumetric efficiencies of the diaphragm compressor decrease with an increase in pressure ratio, with maximum values reaching 70% and 65% respectively. Under constant pressure ratio conditions, the exhaust temperature is found to increase with the rise in suction temperature. For a given suction temperature, a higher-pressure ratio resulted in a higher exhaust temperature. Furthermore, the cooling effect of the wrap-around cooling pipeline is found to be more pronounced under high pressure ratio conditions, with a maximum temperature reduction of 189.5 °C

Infertility-Related Stress and Life Satisfaction among Chinese Infertile Women: A Moderated Mediation Model of Marital Satisfaction and Resilience

The present study investigated the effects of infertility on Chinese women&#39;s life satisfaction. Infertile women (n = 466) who were seeking medical help completed a survey that included the Fertility Problem Inventory (FPI), the Dyadic Adjustment Questionnaire (DAS), the Connor-Davidson Resilience Scale (CD-RISC), the Satisfaction with Life Scale, and demographic variables. We used a moderated mediation model to test our hypotheses, with life satisfaction as the dependent variable, representations about the importance of parenthood as the independent variable, the impact of infertility on life domains as a mediator, and marital satisfaction and resilience as moderators. Results showed that representations about the importance of parenthood and the impact of infertility on life domains are two main types of infertility-related stress, which could play independent roles in predicting life satisfaction. Representations about the importance of parenthood had a negative indirect effect on life satisfaction through the impact of infertility on life domains, and the indirect effect of the impact of infertility on life domains was moderated by marital satisfaction and resilience. Specially, representations about the importance of parenthood had a weaker indirect effect (through the impact of infertility on life domains) on life satisfaction in individuals with higher marital satisfaction or resilience. Therefore, the type of infertility-related stress and both marital satisfaction and resilience should be addressed in psychological interventions for women coping with infertility in mainland China.</p

Original Article Reliability and validity of the Chinese version of reporting of clinical adverse events scale (C-RoCAES)

Abstract: Background: Adverse event is a crucial issue affecting patient&apos;s safety of healthcare services. To assess nurses&apos; attitude of reporting adverse events is important to establish a safe environment for patients. However, no relevant instrument has been validated and used in China. This study was to examine validity and reliability of Chinese version of Reporting of Clinical adverse Event Scale (C-RoCAES). Material and methods: Chinese version of 25-item RoCAES was used in a sample of 1557 nurses. Confirmatory factor analysis (CFA) and exploratory factor analysis (EFA) were selected for construct validity test. Internal consistency was also examined. Results: After CFA and EFA, two items were removed and two items loaded on different factors in our sample. Five factors were generated, including perceived blame, perceived criteria for identifying events that should be reported, perceptions of colleagues&apos; expectations, perceived benefits of reporting and perceived clarity of reporting procedures. Cronbach&apos;s alpha for the total scale and subscales ranged from 0.70 to 0.85. Conclusion: C-RoCAES is applicable to healthcare services of China. The instrument provide information for the providers of healthcare services to develop staff education regarding patient safety, and also help them to evaluate strategies of preventing adverse events in clinical practice in China

RuxV2−xO5 nanowire/templated carbon composite electrodes for supercapacitors

V2O5 nanowires were doped with Ru4+ using a hydrothermal process. RuxV2−xO5 composites were characterized by x-ray diffraction, energy-dispersive x-ray analysis, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The electrochemical performance of the RuxV2−xO5 nanowires/carbon composites were evaluated by cyclic voltammetry and galvanostatic charge-discharge techniques. The RuxV2−xO5/carbon exhibited a maximum specific capacitance of 351 F·g−1 at a scan rate of 5 mV/s in a symmetric coin cell device. The asymmetric hybrid supercapacitor device achieved a specific cell capacitance of 237 F·g−1 at a scan rate of 5 mV/s, which delivers a high energy and power of 74.8 Wh·kg−1 and 5994.5 W·kg−1, respectively

Quasi-Solid-State “Water-in-Swelling-Clay” Electrolytes Enabling Ultrastable Aqueous Zinc-Ion Batteries

The poor reversibility of Zn metal anodes arising from water-induced parasitic reactions poses a significant challenge to the practical applications of aqueous zinc-ion batteries (AZIBs). Herein, a novel quasi-solid-state water-in-swelling-clay electrolyte (WiSCE) containing zinc sulfate and swelling clay bentonite (BT) is designed to enable highly reversible Zn metal anodes. AZIB full 2 cells based on the WiSCE exhibit excellent cyclic stability at various current densities, long shelf life, low self-discharge rate, and outstanding high-temperature adaptability. Particularly, the capacity of WiSCE-based AZIB full cells retains 90.47% after 200 cycles at 0.1 A/g, 96.64% after 2000 cycles at 1 A/g, and 88.29% after 5000 cycles at 3 A/g. Detailed density functional theory calculations show that strong hydrogen-bonds are formed between BT and water molecules in the WiSCE. Thus, water molecules are strongly confined by BT particularly within the interlayers, which significantly inhibits water-induced side reactions and thus greatly improves cyclic stability. Compared to the state-of-the-art water-in-salt electrolyte, the WiSCE can provide a significantly higher capacity at the full-cell level with a substantially reduced cost, which is promising for the design of next-generation high-performance AZIBs. This work provides a new direction for developing cost-competitive AZIBs as alternatives in grid-scale energy storage

A multi-band atomic candle with microwave-dressed Rydberg atoms

Stabilizing important physical quantities to atom-based standards lies at the heart of modern atomic, molecular and optical physics, and is widely applied to the field of precision metrology. Of particular importance is the atom-based microwave field amplitude stabilizer, the so-called atomic candle. Previous atomic candles are realized with atoms in their ground state, and hence suffer from the lack of frequency band tunability and small stabilization bandwidth, severely limiting their development and potential applications. To tackle these limitations, we employ microwave-dressed Rydberg atoms to realize a novel atomic candle that features multi-band frequency tunability and large stabilization bandwidth. We demonstrate amplitude stabilization of microwave field from C-band to Ka-band, which could be extended to quasi-DC and terahertz fields by exploring abundant Rydberg levels. Our atomic candle achieves stabilization bandwidth of 100 Hz, outperforming previous ones by more than two orders of magnitude. Our simulation indicates the stabilization bandwidth can be further increased up to 100 kHz. Our work paves a route to develop novel electric field control and applications with a noise-resilient, miniaturized, sensitive and broadband atomic candle

Arabidopsis Raf-Like Mitogen-Activated Protein Kinase Kinase Kinase Gene Raf43 Is Required for Tolerance to Multiple Abiotic Stresses.

Mitogen-activated protein kinase (MAPK) cascades are critical signaling modules that mediate the transduction of extracellular stimuli into intracellular response. A relatively large number of MAPKKKs have been identified in a variety of plant genomes but only a few of them have been studied for their biological function. In the present study, we identified an Arabidopsis Raf-like MAPKKK gene Raf43 and studied its function in biotic and abiotic stress response using a T-DNA insertion mutant raf43-1 and two Raf43-overexpressing lines Raf43-OE#1 and Raf43-OE#13. Expression of Raf43 was induced by multiple abiotic and biotic stresses including treatments with drought, mannitol and oxidative stress or defense signaling molecule salicylic acid and infection with necrotrophic fungal pathogen Botrytis cinerea. Seed germination and seedling root growth of raf43-1 were significantly inhibited on MS medium containing mannitol, NaCl, H2O2 or methyl viologen (MV) while seed germination and seedling root growth of the Raf43-OE#1 and Raf43-OE#13 lines was similar to wild type Col-0 under the above stress conditions. Soil-grown raf43-1 plants exhibited reduced tolerance to MV, drought and salt stress. Abscisic acid inhibited significantly seed germination and seedling root growth of the raf43-1 line but had no effect on the two Raf43-overexpressing lines. Expression of stress-responsive RD17 and DREB2A genes was significantly down-regulated in raf43-1 plants. However, the raf43-1 and Raf43-overexpressing plants showed similar disease phenotype to the wild type plants after infection with B. cinerea or Pseudomonas syringae pv. tomato DC3000. Our results demonstrate that Raf43, encoding for a Raf-like MAPKKK, is required for tolerance to multiple abiotic stresses in Arabidopsis